1. Field
Embodiments of the present disclosure relate to a compressor and a control method thereof, and more particularly, to a compressor capable of reducing oil foaming occurring when the compressor is controlled, while reducing the waiting time taken until the heating of the compressor is completed, and a control method thereof.
2. Description of the Related Art
A compressor represents a mechanical apparatus designed to increase the pressure by compressing refrigerant of a gas state. The compressor includes a casing configured to seal the refrigerant and the oil while forming an accommodation space therein, a compressing part provided at an inside the casing to compress the refrigerant, and a motor part provided at an inside the casing to provide the compression part with a driving force.
If the compressor is placed at a low temperature for a long period of time while in a power-off state, the temperature of oil stored in the casing is lowered. If the temperature of oil is lowered, the refrigerant dissolves in the oil. In a state of the refrigerant dissolving in the oil, if the compressor is driven at a high speed, the pressure and the temperature at an inside of the casing are rapidly changed. As a result, the refrigerant dissolving in the oil is rapidly separated from the oil, and an oil foaming occurs, thereby causing the oil in a foam state to be discharged all together through an outlet port. If the oil in a foam state is discharged all together through the discharge port of the compressor, the oil is scarce within the casing of the compressor until the oil is collected by passing through a refrigeration cycle. Such a lack of oil causes a bearing part of the compressor to be worn away.
Accordingly, in order to prevent the oil foaming, the casing of the compressor needs to be heated to increase the temperature of the oil to a predetermined degree, so that the oil is separated from the refrigerant. In order to heat the casing of the compressor, several types of methods may be used. In a first example, which is referred to as a crank case heater (CCH) method, a heater is installed at an outside the compressor, and in a stop state of the compressor, the casing of the compressor is heated by use of the heater. In a second example, which is referred to as a wiring heating method, in a stop state of the compressor, a predetermined electric current flows through a wiring of the motor part, and the casing of the compressor is heated by use of the heat generated from the wiring due to the flow of the electric current.
However, the CCH method and the wiring heating method take a long waiting time until the heating is completed. In addition, in the case of using the wiring heating method in a scroll compressor having the compressor part at the upper side thereof, the oil of the compression part flows down, thereby causing a wrap, at which a stationary scroll makes contact with an orbiting scroll, to be worn away.